Paper web guide



w. c, ROBINEJI-TE PAPER WEB GUIDE Fi led May 5 950 3 Shee.t eet l Ian. 19, 1954 w. c. ROBINETTE PAPER WEB GUIDE Filed May 5, 1950 colvsrmvr 51 680 GOV/ZA/OB. MIXER.

a Sheets-Sheet z 4107' OR CONTROL 6/46 C; U/ 7' 16/2. 1/0 ua/0a.

INVENTOR w/Luga c. noel/Maire.

ATTORNEY 1 Jan. 19, 1954 w, C 'ROB|NETTE 2,666,598

v PAPER WEB GUIDE Filed-May 5, 1950 I 3 Sheets-Sheet 5 IN\IENTOR ama at flag/Maria B4 ATTORNEY Patented Jan. 19, 1 954 UNITED STATES PATENT OFFICE PAPER, WEB GUIDE Willard C. Robinette, South Pasadena, Calif.

Application May 5, 1950, Serial N0. 160,170

13 Claims. I

a This invention relates to means for guiding the lateral position of a travelling sheet of paper,

' cloth, cellophane, or the like, when being fed through machines onto or off of sup-ply rolls, and moreparticularly, to a paper web guide having an improved stability and accuracy of position limits, and requiring a minimum amount of operating power. Previous attempts at web guiding for printing machines-and similar devices using paper from a supply roll have been restricted to lateral motion of either the original roll or the wind-up roll. This method may be suitable for light rolls. However, when the paper roll weighs a ton or more, the power and weight of equipment to move a large roll becom excessive. It is therefore an object-of the present invention to provide means for guiding and positioning a web of paper or similar article without having t move the entire roll of paper in a sideways direction.

As is well known in those industries passing moving webs over rotating rollers, there is almost always a tendency for the moving webto crawl laterally, over the axial length of the rollers due te slight misalignment of successive roller center lines, or because of unequal longitudinal stretching and rolling characteristics of the material across the width of the web. Thus in unrolling news print into a printing press, it is customary to moisture-spray both ends of the roll to eX- pediteunwinding and decrease tendency to tear.

This moisture spray, as well as the relative humidity of the paper and atmosphere, will cause and affect the rate of lateral creepage of the web over the supporting rolls. of the web will cause changes in stress in the side plates supporting the rolls, and hence change alignment of successive rolls. These and many other imponderable relationships cause the moving web to have a random and indeterminate rate of lateral crawl across the surface of the support rolls. i

'A' web of paper or other such material running over a support roller and creeping laterally at the same time can, of course, be caused to return to a given lateral position by merely movingthe support roller in an endwise direction opposite to the creep direction. This is brought about by the friction existing between the roller and the material, and a proper rate of endwise roller motion will compensate for the undesirable creeping action. However, if'the crawling action continues, the roller will be shifted laterally so far as to causetheroller to move out from under the web and cease to support it. Another object Changes in tension mid-point.

of the present invention is to prevent this web creeping oil the roller by making the roller longer than the web is wide, and providing deflecting means attached to the roller axis so that lateral motion of the roller will also cause the creepage characteristic of the web to reverse So that the creepage or crawling action always is in such a direction as to cause the web to approach the center of the roller.

When the web of papermust be positioned accurately at a certain place in the machine performing the desired operation on the paper, moving the supply roll or take-up roll will not immediately affect the travelling paper at some It is another object of this invention to provide a paper web guide having maximum sensitivity and short time correction period,

thus improving the accuracy of web position atthe desired location.

A further object of my invention is to provide web guiding means in which the error correction speed is readily adjustable to various operations and web tensions, thus providing maximum stability and at the same time eliminating diagonal wrinkling of the material under excessive stresses, or too high a rate of error correction.

Other objects and features of advantage will be noted or specifically pointed out in the detailed description of a preferred embodiment of this invention to follow, and it is to be'understood that the invention is not limited to the specific apparatus shown herein, as various forms may be adopted within the scope of the claims.

Briefly, the present invention comprises a lateral guide roller pivoted at each end to support legs which are laterally pivoted at their lower ends so that this assembly forms three sides of a quadrilateral which is angularly shiftable to change the angle of the guide roller axis in a plane perpendicular to material travel over the roller. The quadrilateral is preferably trapezoidal in shape, with adjustable base length so that optimum conditions can .be established for various requirements. A suitable servomechanism is connected to beactuated by the edge of the material web and the output of the servo is connected to change the guide roller angle in the proper direction to correct errors resulting from sideways creep of the travelling material. For large ranges of web runout in a lateral direction, means are also provided for automatically jogging the supply roll in a side -ways direction if desired; I

My invention may :be more fully understood by reference to accompanying drawings, where- Figure 1 is a perspective view showing the guide roller of the present invention connected to an operating crank of a servo-mechanism.

Figure 2 is a diagrammatic view showing the components of a preferred servo-mechanism for controlling the guide roller of Figure l.

Figurefi is a perspective view of the: opposite side of the roller in Figure 1, showing how a push -button circuit can be operated by the guide roller linkage having a slightly modified crank, to move the supply roll in a lateral direction.

Figure 4 is an end view of the guide roller structure, showing its support geometry when the base length is greater than the roller length.

Figure is another end view showing-the sup-- port geometry when the base length is. less than the roller length.

Referring. first to Figure 1 for a detailed description of this invention, a web i of paper or similar material is shown in dotted lines as progressing to the left and bending upwardly under a guide roller 2. Non-rotating end fittings 3 on the guide roller are pivotally connected, each to one of two sup-port rods l. Each support rod 4 is attached in a triangular swivel assembly 5 having opposed legs 5 extending downwardly and outwardly to rotatably connect to a base plate 7. The swivel assembly 5. at each end of the guide roller 2 is slanted inwardly at the bottom to form .a trapezoid having the guide roller as the longer parallel side, as one of the major modes of operation.

Thus, a movement of the guide roller to the right, for example, will lower the right end and raise the left end to move the material web on the exit side a proportional distance to the right. The swivel assemblies. 5 may be slanted outwardly at. the bottom, as desired, as shown in Figure 4, thereby reversing the direction of roller angle change when moved as described above, as a second major mode of operation.

The base plates l have lateral guide tubes 5 secured in their ends, and two parallel side rods 9 extend through the respective guide tubes 8 at each end of the base plates Ito form Ways along which each base plate may slide in directions perpendicular to material travel. This provides a means of varying the angle of inclination of r each swivel assembly 5.

The side rods ii are fixed in cross channels it secured at the extreme ends of the structure to a body frame l! upon which the base plates 1 also rest for vertical support. 9 function to guide the swivel assemblies 5 while not being subject to a bending load in the vertical direction which might cause binding.

Midway between the side rods e is provided an adjustment shaft i2 extending from end to end through the assembly. Between the two cross channels it, the adjustment shaft I 2 carries a right-hand thread it on one end and a lefthand thread 55 on the other end. Reduced end portions it of the shaft 12 project through the cross channels H3, and retaining collars H hold the shaft in endwise position, while a knurled knob I9 is provided on one end of the shaft l2. Each base plate I contains a shaft hole through which the adjustment shaft passes, and opposite-threaded nuts 2| secured to bothbase plates 1 mate with the respective threaded portions I l and I5 of the shaft.

It is thus seen that turning the knob 19 will Thus the side rods cause the lower ends of the swivel assemblies 5 to approach each other or separate, as the case may be, to vary the base length of the trapezoid. The function of this adjustment will be discussed later.

One swivel assembly carries, near the upper end, a pivoting connection 24 to a substantially horizontal push-pull rod assembly 25. The pushpull rod-assembly 25 consists 10fv an outer hollow section 250 and an inner. section 251) slidable within the outer section 25a. Clamping means, such as a lock screw 250, is provided to make the entire rod assembly rigid at the desired length. The'inner section 251) is pivotally connected to a crank25- attached to be operated by a load shaft 2? of'a servo-mechanism illustrated in Figure l bya box '25. Also. a part of the servo-mechanism is an input shaft to carrying a feeler paddle 3| arranged to rest against one edge of the material web I, so that lateral movement of the web I will cause rotation of the input shaft Feeler paddle 3% is normally held against the web by a small spring 32 exerting only a fraction of'an ounce paddle force against the web i A preferred servo-mechanism to control the web position is shown in Figure 2. Here, a servomotor 34' drives a reduction gear box 340. which in turn drives the load shaft 21. A servo-shaft t5, driven directly by the motor rotor, is provided with a governor drive pulley 36 connected to a governor mixer ill as by a governor belt 39. The governor mixer 3'? in this embodiment briefly comprises an outer ball race 4| which is rotated by the governor belt 35, an inner ball race 42 to ich a governor shaft 44 is connected, and a ball retainer 55 containing the customary balls (not shown) and extended to connectto a substantially circular governor spring 46 of flat spring steel and positioned to extend outwardly with its axis intersecting the governor mixer'axis at a right angle, so that the axis line extended from the governor mixer 3"! will intersect the farthest extension of the governor spring 46. At that intersection point, a governor spring contact Al is mounted on spring 45. Weights 49 are positioned on governor spring at opposite points toflex this spring by centrifugal force when rotated and thus move spring contact 41 over a path aligned with the governor mixer axis. 7 The governor shaft id is connected to be rotated by a motor feed belt 50 driven by a governor motor 5i at a constant speed. The ball bearing governor mixer 3'5 described will drive the governor spring 46 in accordance with the resultant of relative speeds and directons of rotations of both the servomotor 34 and the governor motor 5|. This relationship will be discussed fully later;

Opposed to governor spring contact 41 is a movable contact plate 52 mounted on a control arm 55 attached to an arm shaft 55 coming from a differential 5'5. Movable contact plate 52 is normally forced lightly against. the governor spring contact A? by an arm spring (not shown).

The differential 55 comprises suitable means for rotating the arm shaft 55 by either the input shaft 3% or a lock dial'shaft 5l'to which is fixed a lock dial 55, and may be of any character well known to those skilled in the art. Its arrangement is such that the lock dial 55 on shaft 51 will introduce a variable angular relation between arm shaft 55 and input shaft The control arm M, which is electrically connected to contact plate 52, and governor mixer which is electrically connected to governor spring contact ll, are connected to a motor conas mentioned before.

trol circuit 6|, not shown in detail, by wires 60 which also areconnected to limit switches 63 and 64 that willbedescribed later. The motor con-. trol circuit 6! is connected to power mains 62 and-to theservo-motor 34 town the servomotor ineither direction in accordance with contact or no contact of the governor spring and movable plate contacts 41 and 52, or to hold the servomotor 34 in a mean radial oscillatory zero-speed position at an intermediate contact condition, assuming proper feed-back through feeler paddle 3|, as has been described and claimed in my prior application Serial No. 723,178, filed January 20, 1947 ,(Patent No. 2,575,362, issued November 20, 1951). The method and circuits there shown have been found satisfactory for use with the presently described invention.

' The governor speed due to the constant speed governor motor 5| mentioned previously is greater than the governor speed due to the full speed of servo-motor 34, so as to provide substantial governor spring deflection corresponding to zero servo-motor speed, and so that when the servomotor 34 is running in a directional sense oppo-' site to the governor motor 5|,the governor still has apositive rotational speed equal to this excess of governor motor speed.

In operation, from this zero servomotor speed condition, assume that the feeler paddle 31 is moved by an error in lateral position of the material web I in Figure 1 so that the movable contact plate 52, through the differential 56, is caused to separate from the governor spring contact 41. With the opening of the contacts, the servo-motor 34 starts to rotate in the direction causing the governor spring 46 to slow down. The governor spring contact 41 then moves outwardly toward'the new position of the movable contact plate 52. When the new contact is made, the torque applied to the servomotor 34 will reverse and slow its speed. This new contact position, however, will not be the position to which the movable plate 52 was first moved, because as the servo-motor rotates, it is rotating the load shaft 21, crank 26, and paper web I in the direction to return contact plate 52 towards the zero servo-motor speed position,

The slackening of servomotor speed in the direction mentioned speeds up the governor spring 46 so that the contacts are then momentarily opened.

In this manner, contact is made and broken to give progressively lower and lower servo-motor speeds and lateral paper web travel until, as the movable plate 52 approaches the neutral position, the system again remains quiet and stable at zero servo-motor speed, and correct lateral paper web position. The servo action to return the web to the correct neutral lateral position of zero error is effective (whether the web is moving or stationary) as long as friction between the web I and guide roller 2 is sufli-- cient to prevent slippage betweenthe web and roller.

In addition to moving the guide roller 2 laterally enough to bring the paper web I back to its correct position, servo-motor rotation has tilted the guide roller '2 in the proper direction' I desired lateral position on the roller 2, thus moving the feeler paddle 3| back to neutral and and guide roller position, i. e., the paper web is centered but'the guide'roller has been de- 1 fiected to a newside position.

The action and operation of this particular servo-mechanism have been described in considerably more detail in another of my copending applications, Serial No. 73,617, filed January 29, 1949, and the components used in the practice of the present invention are substantially the same as described and "claimed therein. It can easily be seen from this description, however, that no "hunting of this system can occur, and that it is extremely sensitive due to the dependence upon almost infinitesimal changes in distance between governor spring contact 41 and the movable contact plate 52, a combination of characteristics heretofore unobtainable in other servo-mechanisms, and hence that the material web I will be maintained at the neutral position with a high degree of accuracy.

The limit switches 63 and 64 (Figure 2) are preferably provided in order that the servo-motor 34 will not deflect the guide roller 2 past a fixed maximum side position in either direction in case of any failure. If the materialweb I should break, for example, the feeler paddle 3| would undoubtedly swing so far out of position that the servo-motor 34 would run wild and attempt to rotate the guide roller 2 and swivel assemblies 5 past a structural limit position of the linkage.

Therefore, a first limit switch 63, normally closed, is mounted on one extreme side of the crank 26 in line to be contacted and opened thereby if some failure occurs to permanently close the governor'spring contact 41 and the contact plate 52 to drive the crank 26 in this direction. 'Switch leads 64a and 641) are connected to place the first limit switch 63 in series with one side of the contact wires 60 so that the opening of switch 63 will amount to a separating of the governor spring contact 41 and the contact plate 52, and thus cause the servomotor 34 to reverse direction until switch 63' is again closed. A second limit switch 64, normally open, is mounted on the opposite extreme side of the crank 26 in line to be contacted and closed thereby if some failure occurs to permanently open the governor contacts to drive the crank 26 in this opposite direction. Switch leads 64b and 640 are connected to place the second limit switch 64 across both sides of the contact wires 60 so that closing of switch 64 will amount to a closing of the governor contacts and thus cause the servo-motor to change direction until switch 64 is again opened.

Thus, by means of the two limit switches 63 and 64, any malfunction of the system causing theservomotor 34 to run wild will allow this action to proceed only until one or the other limit switches is operated, at which time the motor will be caused to go into an uninterrupted oscillation about the point where the limit switch is contacted.

The control of the creeping action (so that the web creep is always toward the center of the guide roller 2) is a function of the adjustable base length trapezoid geometry forming the support of the'guide roller. Depending on the tension in the web, diagonal sheer stiffness, elasticity, roll alignment, material thickness, relative humidity, and other variables, theweb I will W creep laterally on the rollers. creep is in the. direction that will increase web tightness, and sometimes in the direction that.

will decrease web tightness. I have found that a change in the inclination of the axis of rotation of: any roller will exert modifying action on the direction and rate of creep of the web.

By adjustment of the relative base length of the'trapezoid with the knob 19, the roller 2 has a rocking action about a virtual center of rotation 83 above the plane of the web (Figure 4), when the base of the trapezoid is longer than the effective roller length. The virtual center of rotation moves to a point 8! below the plane of the. web when the base of the trapezoid is shorter than the eifective roller length, as indicated in Figure 5.

Thus, according to the actual characteristics of the given web i, it is possible toiso adjust the trapezoid base length by knob l9, that the roller 2 will have a virtual center of rotation position enabling the web to always creep toward the center of the roller for any angular displacement caused by the servomotor action. This adjustment may be properly determined by actual trial at the time of installation while the roller 2 is being servo-controlled. With the trapezoid set as a true parallelogram, the direction andrate of web creep is observed. An arbitrary .direction of rotation of knob l9 of several turns will cause the creepage rate to either increase or decrease. The direction causing de crease of creep is the correct one, and a change in the amount'of rotation changes the lateral creep, rate of the moving material for a given servo displacement. The variable position of the trapezoid base length is very desirable since different widths and speeds of material require different radii of rotation for best guiding results.

The swivel assemblies are made triangular, in end elevation, to resist material web forces from any direction. The material may traverse the guide roller 2 from any direction so long as there is enough contact area and force to hold it in non-slipping contact with the roller. For guiding at the proper point in the process machine, the feelerpaddle 3! can be located anywhere along the material (following the guide roller 2-) wherethe, desired accuracy is to be maintained, as mentioned in the introductory objects.

As shown in Figure 1, the entire servo-mechanism is mounted in the box 29, which may be moved laterally as a unit by the rotation of a hand wheel 65 acting on a lead screw (not shown) as is well known in the art.

The purpose of the hand wheel 65 and adjustable rod assembly 25 is to make rough adjustments of the entire servo-mechanism to suit any possible width of material to be fed through the machine. With the lock screw 25c loosened, the box '39 is moved by cranking hand wheel 65 to place the feeler paddle 3! against the material web I in the approximate neutral position of the paddle. Then the lock screw 250 is tightened and the rod assembly 25 remains at that length.

The lock dial 59, shown in Figure 2, provides an easy method of fine adjustment for desired lateral position of the guided web I. Assuming the feeler paddle 3! to be in a stationary position resting against the material web I, a rotation of the lock dial 59, will change the position of. the movable. contact platefilthrough the. differential 56. This willinitiate a servo; action. as

Sometimes the.

8 previously described, to change the travelling, web i and the paddle 3| to a new neutral position in accordance with the direction and magnitude of, rotation. of the dial 59.

It is thus seen that the desired lateral position of the guided web I can be accurately and easily obtained by rotation of lock dial 59 in the proper direction.

To reduce Wrinkles caused by diagonal shear forces in applications where very large ranges of material runout are encountered, a roll position ing device is provided as shown in Figure 3. Here, a supply roll 6%, for example, is mounted on a non-rotating supply shaft 61 which is movable laterally in shaft bushings 89. This lateral movement is eifected by a control arm '20 coming from a power means H and pivotally connected to one endof the supply shaft 61. The power means H is controlled in two directions by separate spring-loaded control switches 12 and 12a wired into the power means by switch leads '64.

In the present embodiment, the crank 2611 which operates the guide roller 2 is furnished with opposite facing switch actuators in the plane of crank rotation. The respective control switches i2 and We are located at a predetermined distance from each of these actuators '15, so that at a large deflection position in either direction, one of the control switches 72 or 12a will be closed to energize the power means H to move the supply roll 66 sideways in the proper direction to supplement the guide roller correction.

dince most heavyprinting presses and paper handling machinery are equipped with to l H. P. motors, push-button operated,,for jogging the paper roll sideways, these same motor circuits can be automatically operated by the guide roller linkage in the present invention. Therefore, automatic supply or take-up roll guiding is obtained over very large ranges of web runout.

. It is to be noted that the pivoting guide roller system as herein described is entire y capable of correcting any lateral web error, or drift, in the absence of sideways roll adjustments. It is merely to prevent bad diagonal wrinkles resulting from extremely large runouts that the lateral roll adjusting means may be incorporated. Of course, badly aligned rolls in the main machine will also cause these wrinkles.

From the above description it will be apparent that there is thus provided a device of the character described possessing the particular features of advantage before enumerated as desir- I able, but which obviously is susceptible of modification in its form, proportions, detail construction and arrangement of parts without departing from the principle involved or sacrificing any of its advantages.

While in orderto comply with the statute, the invention has been described in languag more .or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprise the preferred form of putting the invention into effect, andthe invention is, therefore, claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims.

What is claimed is:

- 1. A web guide comprising guide roller around which said web is arranged to make a turn, a support member pivotally connected to each end of said roller, a base, said support members. being of substantially equal lengthsv andpivotally connected to said base toform a trapezoidal shape of which said support members are the non-parallel sides, a servo-mechanism having input and output elements, said output element connected to rock said roller by rotating said support members laterally about their base connections, and lateral web position sensing means connected to drive said input element.

2. A web guide comprising a guide roller around which said web is arranged to make a turn, a support member pivotally connected to each end of said roller, a base, said support members being of substantially equal lengths and pivotally connected to said base to form a trapezoidal shape of which said members are the non-parallel sides, means for sensing the lateral position of said web, and means for rocking said roller by rotating said support members laterally about their base connections in accordance with said sensing means.

3. Apparatus in accordance with claim 2 wherein said base is adjustable in length.

4. Apparatus in accordance with claim 2 wherein said base is continuously symmetrically adjustable in length about the center line of said trapezoidal shape.

5. Apparatus in accordance with claim 2 wherein said rocking means comprises a crank and connecting rod connected to one of said sup' port members, said sensing means comprising a substantially flat paddle adapted to rub against the edge of said web, and a shaft connected to be rotated by said paddle when said web moves in a lateral direction. a

6. Apparatus in accordance with claim 5 wherein said paddle is adjustably connected to said shaft, to change the guided position of said web. I

7. Apparatus in accordance with claim 5 including emergency limit means connected to said rocking means to control the direction of movement thereof, an operating member moving in the same manner as said crank, saidlimit means being located to. make operating connection with said operating member at opposite extreme-limit positions to prevent movement of said rocking means past either of said limit positions, said limit positions being outside of the normal operating range of said web guide.

8. Apparatus in accordance with claim 2 including a roll around which said web is wound, means for moving said roll sideways in either of two. directions when energized, and means for energizing said roll moving means in each of said directions respectively at relatively widespread positions only of said rocking means.

- 9. Apparatus in accordance with claim 8 wherein said roll moving means comprises electrically controlled power means, said rocking means comprises. a crank, and said energizing means comprises switching means for energizing said power means in either of twodirections, said switching I means being arranged to be contacted and 0perated by said crank to move said roll in the same lateral direction as web movement caused by crank and guide roller deflection.

10. Apparatus in accordance with claim 9 wherein a predetermined crank deflection on each side of a neutral position is allowed before contact with said switching means.

11. Apparatus in accordance with claim 1 wherein said servo-mechanism comprises a first electrical contact connected to be displaced back and forth in accordance with the position of said input element, a constant speed motor, a reversible electric servo-motor, a rotation mixer having a rotary output member and two rotary input members, one of said input members driven by said constant speed motor and the other input member driven by said servo-motor, said output member adapted to be driven at a velocity resultant from the two input member velocities, the speeds of said motors being such that said output member is driven in one direction only regardless of the direction of servo-motor rotation, an expansible governor driven by said output member, a second electrical contact positioned on said governor at the expansible end thereof to move back and forth in accordance with the velocity of said output member and in a line with the center of rotation of said output member, said two contacts being located opposite each other and movable substantially co-linearly, a servomotor control circuit including said two contacts and electrically connected to rotate said servomotor in one direction when said contacts are closed and in the opposite direction when said contacts are open, said servo-motor being mechanically connected to drive said output element.

12. Apparatus in accordance with claim 1 wherein an element is provided moving with said roller, limit switches actuated by said element and connected to drive said input element to limit the rocking range of said roller.

13. Apparatus in accordance with claim 2 wherein an element is provided moving with said roller, limit switches actuated by said element and connected to said rocking means to limit the rocking range of said roller.

WILLARD c. ROBINETTE.

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